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[Qemu-devel] [PATCH v3 31/44] nbd: Share common reply-sending code in se
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v3 31/44] nbd: Share common reply-sending code in server |
Date: |
Fri, 22 Apr 2016 17:40:39 -0600 |
Rather than open-coding NBD_REP_SERVER, reuse the code we
already have by adding a length parameter. Additionally,
the refactoring will make adding NBD_OPT_GO in a later patch
easier.
Signed-off-by: Eric Blake <address@hidden>
---
v3: rebase to changes earlier in series
---
nbd/server.c | 48 +++++++++++++++++++++++-------------------------
1 file changed, 23 insertions(+), 25 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 1d30b6d..4435d37 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -195,12 +195,15 @@ static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc,
size_t size)
*/
-static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
+/* Send a reply header, including length, but no payload.
+ * Return -errno to kill connection, 0 to continue negotiation. */
+static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
+ uint32_t opt, uint32_t len)
{
uint64_t magic;
- uint32_t len;
- TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt);
+ TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
+ type, opt, len);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
@@ -217,7 +220,7 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t
type, uint32_t opt)
LOG("write failed (rep type)");
return -EINVAL;
}
- len = cpu_to_be32(0);
+ len = cpu_to_be32(len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (rep data length)");
return -EINVAL;
@@ -225,37 +228,32 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc,
uint32_t type, uint32_t opt)
return 0;
}
+/* Send a reply header with default 0 length.
+ * Return -errno to kill connection, 0 to continue negotiation. */
+static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
+{
+ return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
+}
+
+/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
+ * Return -errno to kill connection, 0 to continue negotiation. */
static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
{
- uint64_t magic;
size_t name_len, desc_len;
- uint32_t opt, type, len;
+ uint32_t len;
const char *name = exp->name ? exp->name : "";
const char *desc = exp->description ? exp->description : "";
+ int rc;
TRACE("Advertising export name '%s' description '%s'", name, desc);
name_len = strlen(name);
desc_len = strlen(desc);
- magic = cpu_to_be64(NBD_REP_MAGIC);
- if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- LOG("write failed (magic)");
- return -EINVAL;
- }
- opt = cpu_to_be32(NBD_OPT_LIST);
- if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- LOG("write failed (opt)");
- return -EINVAL;
- }
- type = cpu_to_be32(NBD_REP_SERVER);
- if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
- LOG("write failed (reply type)");
- return -EINVAL;
- }
- len = cpu_to_be32(name_len + desc_len + sizeof(len));
- if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
- return -EINVAL;
+ len = name_len + desc_len + sizeof(len);
+ rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len);
+ if (rc < 0) {
+ return rc;
}
+
len = cpu_to_be32(name_len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (name length)");
--
2.5.5
- Re: [Qemu-devel] [PATCH v3 07/44] nbd: Limit nbdflags to 16 bits, (continued)
- [Qemu-devel] [PATCH v3 10/44] fdc: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 15/44] m25p80: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 14/44] sd: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 13/44] pflash: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 16/44] atapi: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 18/44] qemu-img: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 23/44] qemu-io: Add missing option documentation, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 29/44] nbd: Avoid magic number for NBD max name size, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 31/44] nbd: Share common reply-sending code in server,
Eric Blake <=
- [Qemu-devel] [PATCH v3 06/44] nbd: Clean up ioctl handling of qemu-nbd -c, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 09/44] block: Allow BDRV_REQ_FUA through blk_pwrite(), Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 12/44] onenand: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 17/44] nbd: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 11/44] nand: Switch to byte-based block access, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 20/44] block: Switch blk_read_unthrottled() to byte interface, Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 22/44] block: Kill blk_write(), blk_read(), Eric Blake, 2016/04/22
- [Qemu-devel] [PATCH v3 21/44] block: Switch blk_write_zeroes() to byte interface, Eric Blake, 2016/04/22